Maintenance workers paint signs on the road in Chamdo. (Photos: China Daily)

Mo Wei (left), an officer responsible for maintaining a section of National Highway 318 in Pashoi county, Chamdo city, Tibet autonomous region, shows a new recruit how to fill cracks with asphalt.

The 72 switchbacks that zigzag sharply through the Chamdo section of National Highway 318.

Workers maintain a 40-kilometer section of road in the Tangula Mountains, the highest point of the Qinghai-Tibet Highway.

Officers seal a section of the Qinghai-Tibet Highway.